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Poster: Scribble Date: Apr 4, 2012 8:05am
Forum: prelinger Subject: Re: New Films

Fantastic news Rick...many thanks!

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Poster: Spuzz Date: Apr 5, 2012 11:32pm
Forum: prelinger Subject: Re: New Films

Ah Scribble, damn you, now you got me all excited and reviewing films again!

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Poster: Scribble Date: Apr 5, 2012 11:42pm
Forum: prelinger Subject: Re: New Films

Ah Spuzz! You're back! I'm looking forward to your entertaining comments and fun to read reviews!

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Poster: Frank Panucci Date: Apr 7, 2012 2:10pm
Forum: prelinger Subject: Re: New Films

Wonderful to see new entries.

Is it just me, or are a few of the transfers, such as CITY WITHIN A CITY, a little messed up? There are motion artifacts that resemble those produced by CMOS imagers in cheap video cameras: the "Jello" effect. This is visible on three systems with different media players. The videos are at 29.97 fps from what are most likely 24fps originals, but examination reveals no visible interlacing. Wild guess - the fields were reversed during pulldown, then blended.

This is also present in the new transfer of WESTINGHOUSE TRAVELERS' CHOICE 66. I still have the older MPEG2 transfer downloaded from this site, which plays flawlessly.

Screen shot from the new upload of TRAVELERS' CHOICE made in a video editing program, with all blending and interlacing options turned off:
http://imageshack.us/photo/my-images/703/prelingerartifact2012.jpg/

This shows up in some other recent uploads, but I forget which ones right now. The defects are also visible in the streaming previews.

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Poster: Frank Panucci Date: Apr 7, 2012 3:29pm
Forum: prelinger Subject: Re: New Films

The new upload of WHAT'S IT TO YOU also suffers greatly from this problem.
http://archive.org/details/0538_Whats_It_to_You
This video has lots of horizontal motion, which is most affected by whatever glitch infested this recent effort.

The older MPEG2 encode is fine.

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Poster: Frank Panucci Date: Apr 7, 2012 3:54pm
Forum: prelinger Subject: Re: New Films

A IS FOR ATOM. Great cartoon.

The new upload is defective as described above:
http://archive.org/details/0553_A_is_for_Atom

The original uploaded MPEG2 is not:
http://archive.org/details/isforAto1953

The transfers are clearly from the same well-worn print, but the old one is better.

I just spot-checked about twenty of the most recent uploads and they all have the same motion artifacts. I can't complain at this price, but these new Prelinger-section uploads are not of much use for re-purposing footage.

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Poster: Scribble Date: Apr 9, 2012 12:37am
Forum: prelinger Subject: Re: New Films

Yes, I have to confirm these observations...I've never had too much trouble removing pulldown from the old MPEG2 encoded films...but these new mp4s, while I must say look terrific resolution wise, have a pulldown cadence that does not conform to any normal pattern, there is definitely frame blending going on and even without trying to remove pulldown, plays back quite jittery at 29.97. Just as Frank notes, it's hard to complain regarding a free resource, I am eternally grateful, but it's a real shame that clean, 24fps, or even 30fps slowed down to 24fps, are not happening with this new round of footage...

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Poster: Frank Panucci Date: Apr 9, 2012 10:45am
Forum: prelinger Subject: Re: New Films

I keep a number of Prelinger-supplied films on my hard drive permanently because I use footage from them so often. So, I have conveniently at hand for side-by-side comparison the WESTINGHOUSE TRAVELERS' CHOICE 66 MPEG2 encode I downloaded eight years ago, and the MP4 encode uploaded recently.

MPEG2 has two channels of sound.
MP4 has only a left channel and a blank right.
It seems to be mono sound anyway, but the empty channel is confusing.

MPEG2 audio is sharp and distinct.
MP4 audio is slightly muffled and distorted. Its waveform reveals some degree of additional compression compared to the MPEG2 audio.

MPEG2 is half NTSC horizontal resolution with faded color.
MP4 has better color, and is sharper, at full 720 res.
When things aren't moving, the image is very good.

MPEG2 is a true 60i video file with proper pulldown, which can be loaded in a video program and broken out into a 24fps progressive image sequence.
MP4 is a 29.97 progressive file, with blended fields, which very much appear to have been derived from a reversed-field transfer. Almost any motion is severely affected. Pulldown can absolutely not be removed.

I prepared a side-by-side screen grab of the same frame from both encodes. Maybe it will help diagnose problems on the encoding end for future Prelinger offerings:
http://img850.imageshack.us/img850/4939/prelingerartifact2012b.jpg


This post was modified by Frank Panucci on 2012-04-09 17:43:17

This post was modified by Frank Panucci on 2012-04-09 17:45:41

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Poster: Frank Panucci Date: Apr 9, 2012 8:20am
Forum: prelinger Subject: Re: New Films

http://archive.org/details/0657_Carving_Magic
CARVING MAGIC

Same issues as described above, compared to the original upload in 2003 or so.

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Poster: Frank Panucci Date: Apr 9, 2012 8:24am
Forum: prelinger Subject: Re: New Films

http://archive.org/details/0664_HM_Medicus_collection_New_York_Worlds_Fair_1939-40_Reel_2
Medicus collection: New York World's Fair, 1939-40 (Reel 2)

Same technical glitches as above, compared to the original encode of the same film also available here.

I'm not trying to be a pain, really. I'm sure you would prefer to post films as watchable and technically useful as those for which the Prelinger-branded section of the archive has been known for years. The number of improperly-encoded videos is growing larger at an upsetting rate of speed.




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Poster: Frank Panucci Date: Apr 9, 2012 9:30am
Forum: prelinger Subject: Re: New Films

I checked over my recent Prelinger backups. As a matter of routine I download every film at archive.org that looks remotely interesting, in case a useful gem is taken down for some reason, or if the archive itself becomes unavailable. I often don't examine the files for weeks or months. I also checked over another hundred or so entries I hadn't downloaded yet.

It appears, unfortunately, that the Prelinger-section films afflicted with the technical errors detailed above number over four hundred, and include everything posted since December 2011.

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Poster: Administrator, Curator, or StaffRick Prelinger Date: Apr 9, 2012 3:40pm
Forum: prelinger Subject: Re: New Films

I'm just now seeing the new posts in this thread. We are looking into this and will try to figure out where this is happening.

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Poster: Scribble Date: Apr 10, 2012 6:54am
Forum: prelinger Subject: Re: New Films

Rick, I have to again agree with Frank, the visual quality of the new mp4s is undeniably better, a vast improvement over the mpegs, but yes, unfortunately I am getting exactly the same pull-down issues that Frank has so perfectly described. Luckily, I have many of the mpeg2 versions of films I make use of which, unfortunately despite their inferior quality, I would be more likely to use because of their correct pulldown which is very easy to remove.

I really appreciate that this resource has been available for so many years, and yes, I hate being a pain about it, but it would be so incredibly valuable for low/no budget filmmakers to have these files with either proper pulldown...or, even better, no pulldown at all. It would make the files smaller and many productions are being edited at 24fps these days...with pulldown added at the end of the process.

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Poster: Administrator, Curator, or StaffRick Prelinger Date: Apr 23, 2012 7:53am
Forum: prelinger Subject: Re: New Films

Just to be clear, what we're doing is digitizing tapes of telecine transfers made between 1984 and 2011. All are NTSC SD transferred at 29.97 fps, but beyond that they could be anything; they were transferred by various facilities at various times on various machines. While we can control the parameters by which we derive mp4s to upload, the transfers are what they are.

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Poster: philips272 Date: Jun 2, 2012 3:30pm
Forum: prelinger Subject: Re: New Films

The quality is much better but this clip appears to be reel 3 according to the older mpeg file

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Poster: Frank Panucci Date: Apr 7, 2012 3:36pm
Forum: prelinger Subject: Re: New Films

Also afflicted:
http://archive.org/details/1924_Misc_Stock_Shots

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Poster: Frank Panucci Date: Apr 7, 2012 3:46pm
Forum: prelinger Subject: Re: New Films

Another:
http://archive.org/details/0548_American_Engineer

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Poster: Frank Panucci Date: Apr 7, 2012 3:40pm
Forum: prelinger Subject: Re: New Films

Another magic wobbly screen:
http://archive.org/details/1221_Its_a_Wonderful_World
I have the original MPEG2 version on hand. It's fine.

Has anyone else noticed this?

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Poster: Administrator, Curator, or StaffA/V Geeks Date: Apr 9, 2012 3:49pm
Forum: prelinger Subject: Re: New Films

Hey folks,
It looks like the deinterlacing and denoising functions of ffmpeg is making the jello effect. We'll turn that feature off and do some rederiving..

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Poster: Scribble Date: Apr 10, 2012 7:20am
Forum: prelinger Subject: Re: New Films

I hope that does the trick! Thanks for looking into this guys...really, really appreciate it!

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Poster: Frank Panucci Date: Apr 10, 2012 9:34am
Forum: prelinger Subject: Re: New Films

Great!

Is there any obstacle to encoding the files as native 24P? I understand that if these are derived from master NTSC tapes, that won't be trivial - but if any of the problem videos are new scans, 24P video plays back well on almost any device and it's easy to further manipulate. The 16-18fps of the home movies may complicate issues. Maybe a 14.98 frame rate encoded to 29.97 with no temporal resampling would be cool.

Your efforts are very much appreciated - even with the recent hiccup. Scanning and uploading all these films has to be a huge amount of work - - -

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Poster: Frank Panucci Date: Apr 10, 2012 1:00pm
Forum: prelinger Subject: Re: New Films

Ah! Wonderful World of Trains is a heart-breaker, in that it shares the video issues described above. What a wonderfully weird little film.